The present disclosure relates to a cushioning material that is used, when a relatively heavy product such as an electronic device is packed, to protect the side surfaces, the bottom surface and the top surface of the product.
Conventionally, as a method of packing an electronic device or the like, a method of arranging a cushioning material absorbing an impact and vibrations from the outside during transportation between an outer box such as a corrugated cardboard case and the electronic device (packed item) is generally used. As the cushioning material, a material that is obtained by folding a corrugated cardboard, a pulp-molded cushioning material that utilizes used paper as a material and that can be recycled or the like is used.
However, for the purpose of packing a heavy item, a cushioning material is widely used that includes: a base material which is formed with a corrugated cardboard and a sheet material made of a foamed resin; and a plurality of columnar support portions which are formed integrally with or fixed to the base material.
In the packing using the cushioning material described above, in general, the base material is in contact with the side surfaces of the packed item to be cushioned, the columnar support portions are arranged on portions, having a high strength, of the side surfaces of the packed item and the side surfaces of the packed item are received by the entire surface of the base material.
For example, a packing material is known in which a cross-shaped sheet formed with a corrugated cardboard sheet is wound, in a sleeve shape, around a fan attachment frame that is a packed item, and then they are bound with a binding material; a stacked core (columnar support portion) fitted to the holder surface of the cross-shaped sheet (base material) is used to hold the back surface of a flange portion of the fan attachment frame, and thus the resistance to a compression load is enhanced.
However, depending on the packed item, it is likely that a portion strong enough to have the columnar support portion arranged is not present on a surface to be cushioned or the area of a portion having a high strength is small, with the result that it may be impossible to arrange the cushioning material. In order to overcome this problem, it is necessary to cover the packed item with a foamed cushioning sheet or fill the gap between the packed item and an outer box with foamed resin chips, and thus the amount of cushioning material used is increased. Consequently, the packing cost is increased, and it is not preferable in terms of environment load.
One way is to increase the size of the base materials compared with the surface of the packed item to be cushioned and arrange the columnar support portion outside the outer edge portion of the packed item. However, when a load is applied to the columnar support portion, the base material is bent at a joint portion to the inner edge of the columnar support portion, and the columnar support portion falls to the side of the packed item, with the result that it is disadvantageously impossible to obtain a sufficient cushioning effect.